A valve positioner returns a 4–20 mA feedback signal while the PLC command is held at 90%. The measured feedback is 18.4 mA. This page owns that exact calculation job and opens the matching server-graded case rather than a generic calculator.
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The lower range value is 0 and the upper range value is 100 % open. The engineering span is the difference between those values; it is not automatically zero-based.
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Open the registered Control-valve position transmitter case so the grader—not the browser copy—owns the expected result.
Open the exerciseSubtract the 4 mA live zero from 18.4 mA, then divide by the 16 mA measurement span. Keep enough precision until the engineering conversion is complete.
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Calculate the fraction separately before typing the final engineering value into the lab.
Open the exerciseMultiply percent span by the configured engineering span, then add 0 % open. The registered expected result is 90 % open within ±0.1%.
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Submit the value and inspect the range, live-zero and tolerance checks returned by the server.
Open the exerciseA calculation mismatch can come from signal measurement, transmitter configuration, PLC card range, program scaling or unit conversion. Preserve the measured current, range, result and timestamp before changing any layer.
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Create an account to retain the attempt, then use a paid workspace to compare cases, keep full history and assign the exercise.
Open the exerciseCore concepts
The simulator creates a repeatable result; these concepts make that result transferable to real vendor software and supervised practical work.
Four milliamps represents the lower engineering value, leaving near-zero current available as fault evidence.
For this Control-valve position transmitter, the span is 100 % open.
The case records the input, expected value, units and ±0.1% acceptance statement instead of returning an unexplained number.
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Run the foundation exercise publicly, then use a subscription for advanced challenges, saved configurations, full attempt history, sharing, assigned paths and team reporting.
Related learning surfaces
Competency and practice field guide
Direct answer
The learner can scale output and feedback, test rising and falling points, quantify deviation and distinguish electrical, pneumatic and mechanical failures.
Written for instrumentation learners checking a valve command and feedback across a declared 0–100 percent travel range.
Command range, loop output, action direction, positioner input, supply pressure, zero and span, travel feedback, tolerance, hysteresis and process isolation.
0–100 percent request through analog output, loop current, positioner, actuator travel, position feedback and independent process indication.
Declared points in both directions reach stable travel within tolerance with coherent current, command and feedback.
Air loss, reversed action, sticky stem, deadband, saturated output, failed feedback, manual override, split range, restart and mechanical limit.
A request, output scale, loop, positioner, air, actuator, travel, feedback, tolerance or process mismatch.
The test completed with approved isolation, exact manufacturer procedure and independent process safeguards.
Apply authorized bounded command points in both directions and compare raw output, loop current, indicated travel and independent physical position within a declared tolerance.
Not necessarily. Flow depends on valve characteristic, pressure conditions and system resistance; travel feedback proves position, not linear process flow.